package com.tedu.api;

import org.junit.Test;

public class 作业 {
    @Test
    public void testlength() {
        String str = "Hello Java";
        System.out.println(str.length());
        char c=str.charAt(4);
        System.out.println(c);
        int index = str.indexOf('o');
        if (index != -1) {
            String subStr = str.substring(index);
            System.out.println(subStr); }
        str=str.substring(0,5);
        System.out.println(str);
        str=str.substring(6);
        System.out.println(str);
        String trimmedStr = str.trim();
        System.out.println(trimmedStr);
        char charAtIndex6 = str.charAt(6);
        System.out.println(charAtIndex6);
        str=str.trim().toUpperCase();
        System.out.println(str);
        str=str.trim().toLowerCase();
    }
}